Milk assumes a pivotal role in human nutrition from early stages of life, although when going into adulthood the consumption habits can vary according to different perceptions from the consumer or even due to the presence of some intolerances. In this context, this research focuses on the consumption knowledge about the composition and nutritional value of milk and its effect on human health. The objective was to investigate how informed are the French and Portuguese participants and detect similarities or differences according to the country. For this purpose, a questionnaire survey was set up to recruit participants from two countries: France and Portugal. The total number of participants was 543, of which 333 were French and 210 were Portuguese. For treatment of data basic statistics and tests were used to compare the results between the two countries, using the software SPSS. The results showed significant differences between the two countries in what concerns the participant’s knowledge about milk composition and nutritive value and also the effects of milk on human health. From the 13 items used to assess knowledge about composition and nutritive value of milk, significant differences were found between countries for six of them. Regarding the ten items used to evaluate the effects of milk on human health, significant differences were found for seven of them. As so, the knowledge about the effects on human health are more differentiated between the participants from France and Portugal, than the knowledge about the milk composition. Factor analysis showed six groups of questions, with good internal reliability (values of alpha varying from 0.707 to 0.825). It is concluded that participants from different countries, exposed to different environments (societal, political, or educational) can have different perceptions about milk and its effects on health.